border-top-1px($color)
  position : relative
  &:after
    display: block
    position: absolute
    left: 0
    top: 0
    border-top 1px solid $color
    width: 100%
    content: ''

border-bottom-1px($color)
  position : relative
  &:after
    display: block
    position: absolute
    left: 0
    bottom: 0
    border-bottom 1px solid $color
    width: 100%
    content: ''

border-none()
  &:after
    display: none
